1. Field of the Invention
The present invention relates to a vibration-damping electromagnetic actuator that generates driving force of a movable member in relation to a stator through energization to a coil, and a method for manufacturing such a device. The present invention also relates to an active fluid-filled vibration-damping device that applies the force generated by the vibration-damping electromagnetic actuator to a fluid chamber in order to reduce vibration in an offset fashion, and an active vibration-damping device that reduces vibration of a member subject to vibration damping in the offset fashion by the force generated by the vibration-damping electromagnetic actuator.
2. Description of the Related Art
From the past, for an active fluid-filled vibration-damping device, an active vibration-damping device or the like, a vibration-damping electromagnetic actuator has been used as an actuator that generates oscillation force. The vibration-damping electromagnetic actuator includes a tubular stator housed within a housing and a movable member inserted into the stator displaceably relative to the stator. For those stator and movable member, one has a coil member including a coil that forms a magnetic field through energization, while the other has an armature that is displaced relative to the coil member due to the force generated by an effect of the magnetic field formed by the coil. Note that a vibration-damping electromagnetic actuator shown in U.S. Pat. No. 7,348,694 has a structure wherein a tubular stator provided with a coil member is externally disposed about a movable member provided with an armature.
As for U.S. Pat. No. 7,348,694, an outer yoke attached to a coil is attached fitting in contact with a peripheral wall of a housing in the axis-perpendicular direction, so that the position of the stator in the axis-perpendicular direction is set by the housing. Meanwhile, the movable member is elastically positioned with respect to the housing in the axis-perpendicular direction by a support rubber elastic body. Thus, by the stator and the movable member each being aligned with the housing in the axis-perpendicular direction with high accuracy, the stator and the movable member are relatively aligned with each other in the axis-perpendicular direction.
However, in fact, deviation of the relative position of the stator and the movable member is hard to be avoided, due to component dimensional errors, contraction of the support rubber elastic body after molding, or the like. This may cause the problems of variability in the output characteristics, abrasion due to forced contact between the stator side and the movable member side in part of the circumference, and further, strain of the support rubber elastic body, or the like.